EP1960701B1 - Locking apparatus - Google Patents

Abstract

A locking apparatus, particularly of a parking brake device for a vehicle with an automatic transmission, which has a piston unit positioned inside a housing and is axially displaced and locked in a pre-defined axial position, and a catch device that automatically activates when the piston unit is locked to hold the piston unit. The catch device has at least one spring arm actively connected with the piston unit when the piston unit is locked, the spring arm abuts the piston unit in locked position with a catch area. The spring arm has a recess in a longitudinal plane of the spring arm. The piston unit penetrates the recess of the spring arm at least approximately in a radial direction with a section that forms the catch area, so that when the piston unit is locked, the catch area within the longitudinal plane of the spring arm.

Description

The invention relates to a locking device, in particular a parking brake device of a running with an automatic transmission drive train of a vehicle according to the closer defined in the preamble of claim 1. Art.

From the DE 103 47 667 A1 and the EP 1 408 260 A1 For example, a locking device for locking the movement of a piston is known. An armature or its anchor rod of an electromagnet acts on an actuating element, which in turn cooperates with a latching element in such a way that the latching element blocks the movement of the piston in a locking position or the latching element releases the movement of the piston in an unlocking position.

The actuator is designed with a component spring force bias, which is directed in the radial direction to the piston rod. Furthermore, the actuating element is designed either as a plastic part which is sprayed onto a yoke of the electromagnet or clipped onto this, or formed as a stamped part, which is fastened to the yoke via a tension spring provided for reinforcing the spring force bias of the actuating element.

The embodiment of the actuating element as a sprayed or aufgeclipstes plastic part disadvantageously requires an actuator with large wall thicknesses and in the effective range between the locking element and the actuator a large coverage area in order to provide the necessary holding forces, which are generally high in parking brake devices available. However, this is undesirable because of the available standing space is extremely limited, especially in vehicle transmissions.

Furthermore, the design of the actuating element as a biasing spring fixed to the yoke punched part has the disadvantage that high demands are placed on the manufacturing tolerances to ensure the operation of the locking unit. In addition, the actuating element is designed over its entire length with such a component elasticity, that on the one hand, a radial pivoting of a cooperating with the locking element end of the actuating element relative to the other end attached to the yoke is possible. However, this component elasticity leads to such undesirable deformation of the actuating element in the attack region of a bolt, that deactivating the operative connection between the actuating element and the latching element is not possible.

The DE 25 05 358 A1 discloses a working and bracing cylinder in which a hollow piston rod is slidably disposed. The piston rod is actuated in a conventional manner by supplying a pressure medium which can be supplied to the cylinder via an opening. Furthermore, a plurality of elastic, radially spring-loaded latching members are provided in the cylinder, which extend in the longitudinal direction of a chamber. The piston rod has an annular thickening designed in the manner of an annular bead, on which the locking members can slide and thereby open.

The piston facing the side of the thickening is formed so that they cause a locking of the cylinder and piston rod in cooperation with the approximately hook-shaped ends of the locking members, but on the other hand also allows unlocking. The position of the thickening is chosen so that when resting the piston rod against a floor, the locking members engage behind the thickening and against the surface. In order to hold the locking members in their locked position is also as a locking member an approximately provided tubular formed part, the liquid-tight guided in the chamber is displaceable and encloses the locking members in a first position and thereby holds firmly in abutment against the surface of the thickening.

This has the disadvantage that the locking members and the piston rod in the locked state so abut each other that the locking force acting in the detent locking elements generates a bending moment, which is counteract only by corresponding bending stiffness of the locking members, which is why the locking members are to be dimensioned accordingly. However, this disadvantageously leads to high production costs, a high component weight and a large space requirement.

A locking device for two by a pressure medium relative to each other movable members, such. B. a displacement piston and a cylinder to be actuated by a pressure medium lifting or adjusting device, is from the DE 952 575 B known. It is envisaged that upon reaching a certain position of the one acted upon by the pressure medium member, z. B. the sliding piston, relative to the other member, for. B. the cylinder, which is a member by a arranged on this projection and with one of the two members in connection, actuated by a control member locking elements locked.

Again, it is disadvantageous that a bending moment is introduced into the locking elements in the locked state, which can only be supported by a corresponding dimensioning of the locking elements in a manner ensuring the functioning of the locking device.

From the US 5,540,138 a locking device is known in which a executed with a piston rod piston relative to a piston receiving the cylinder over a plurality of circumferentially distributed on the piston arranged resiliently executed locking elements can be locked.

The locking elements are executed at one end fixed to the housing or fixed on the cylinder side and the other end in relation to an outer diameter of the piston around the housing side fixed bearing point made pivotable. The free ends of the locking elements are designed on their sides facing the piston with projections which are in locking position with an annular shoulder of the piston in engagement.

The above-described embodiments of the locking elements and the piston also lead in the locked state of the piston to a bending moment applied to the locking elements, which deforms the locking elements between the bearing and the projections under certain circumstances in a the functioning of the locking device significantly impairing extent when the locking elements do not have a certain flexural rigidity. However, such bending stiffness is only achieved with locking elements which have large component dimensions and are therefore characterized by a high space requirement.

The present invention is therefore an object of the invention to provide a locking device available, which has a low space requirement and is inexpensive to produce.

According to the invention this object is achieved with a locking device according to the features of claim 1.

The locking device according to the invention, in particular a parking brake device of a drive train designed with an automatic transmission of a vehicle, has a lockable in the axial direction in a housing and lockable in a predefined axial position piston unit and in the locked position of the piston unit automatically activating locking device for holding the piston unit on. The latching device is designed with at least one spring arm, which is in operative connection with the piston unit in the locked position of the piston unit, against which the piston unit rests in the locked position with a latching region.

According to the invention, the spring arm is formed with a recess arranged in a longitudinal plane and the piston unit engages through the recess of the spring arm with a latching region forming portion in the radial direction at least approximately so that the latching portion of the piston unit in the locked position of the piston unit at least in one of the longitudinal plane of the spring arm near region, preferably in the longitudinal plane of the spring arm, is arranged.

As a result, it is advantageously achieved that a retaining force acting on the piston unit in the locked state of the locking device is introduced with a low lever arm or directly into the spring arm, whereby essentially only a slight or no bending moment is impressed on the spring arm by the applied load.

This advantageously leads to the fact that the spring arm due to the lower loads compared to known from the prior art locking devices with lower component dimensions and lower material usage is executable and thus is much cheaper to produce and is characterized by a reduced space requirement.

Further advantages emerge from the subclaims.

In an advantageous embodiment of the locking device according to the invention is a contact surface of the spring arm for the locking portion of the piston unit as a one recess in the longitudinal plane of the spring arm running limiting side surface, which is preferably made by punching.

In a further development of the locking device according to the invention, the recess is produced by punching areawise and then bending the punched-out area relative to the longitudinal plane of the spring arm, wherein the piston unit rests in the locked state on the bent out of the longitudinal plane of the spring arm area and the bent portion in its manufacturing bending direction of the Loaded longitudinal plane out. In the last-mentioned embodiment, the holding force acting on the piston unit is introduced into the spring arm with a lever arm depending on the bending radius of the bent region relative to the longitudinal plane of the spring arm, wherein the lever arm is substantially smaller than locking devices known from the prior art.

In order to reduce a notch effect in the force introduction region of the holding force in the spring arm, a punch radius in the region of the contact surface of the latching region of the piston unit on the spring arm is selected accordingly.

In an advantageous embodiment of the locking device according to the invention, the spring arm to increase the flexural rigidity is at least partially formed in cross-section U-shaped, this cross-sectional design can be produced inexpensively and in a simple manner during a bending punching process. Thus, the spring arm is preferably configured in its longitudinal beam region with radially and tangentially directed bends, which give the spring arm its substantially U-shaped cross-section.

Furthermore, there is the possibility of the spring arm as an alternative to or in combination with the latter embodiment of the spring arm at least partially form with at least one extending substantially in the longitudinal direction of the spring arm stiffening bead to perform the spring arm in the attack region of the release element with the advantageous for the release of the operative connection between the spring arm and the piston device flexural rigidity.

Alternatively, or in combination with the above-mentioned two, the flexural strength of the spring arm increasing measures, the spring arm in a further advantageous embodiment of the locking device according to the invention at least partially be performed with at least one extending substantially in the longitudinal direction of the spring arm stiffening, that the spring arm partially with the Loosening of the operative connection between the spring arm and the piston device favoring flexural rigidity is carried out.

In an advantageous development of the locking device according to the invention lies between the in the assembled state of the spring arm with the locking portion of the piston unit in overlapping bearing surface and the locking portion of the piston unit at least line contact, preferably a flat system, before. Thus, the surface pressure between the spring arm and the piston unit in the overlapping area between the contact surface and the latching area compared to a punctiform support is reduced to such an extent that for the production of the piston unit cost-effective and characterized by low-weight materials, such as aluminum-based materials, can be used.

The effect of reducing the surface pressure when activated locking device is reinforced in an advantageous development of the locking device according to the invention characterized in that the spring arm is designed in the region of its contact surface with a contour adapted to the outer shape of the piston unit such that an area of the degree of coverage between the latching portion of the piston unit and the contact surface of the spring arm is maximum.

In a further favorable embodiment of the object according to the invention, the abutment area of the spring arm and the detent area of the piston unit in the overlap area are each such that there is a plane perpendicular to the direction of movement of the piston unit and a contact plane of the overlap area between the detent area and the abutment area at an angle cut from 0 ° to 50. This angle corresponds to a so-called self-locking angle, which must be maintained for safe locking and unlocking or for safe activation or deactivation of the locking device and its size varies depending on the present in the coverage area between the spring arm and the piston unit friction coefficient. The coefficient of friction results from the selected material pairing between the piston unit and the spring arm, wherein a self-locking angle which ensures the functioning of the device according to the invention is approximately 5 ° for a material combination of steel and steel.

In the present case, the plane of contact of the overlapping area is understood to mean that plane which is spanned by the contact surface facing the latching area when the contact surface bears against the latching area.

In this connection, it should be noted that the angle of intersection between the vertical plane and the contact plane of the overlap area under operating load may vary to an extent which deviates from the aforementioned range without adversely affecting the operation of the locking device according to the invention to an undesirable extent. The maximum permissible change range of the angle between the vertical plane and the contact plane is also in Dependence of the coefficient of friction between the spring arm and the piston unit, so that this varies depending on the particular application.

In order to adhere a force to be deactivated for deactivating the latching device and to counteract jamming of the locking device in the region between the spring arm and the release element, the spring arm is formed on a front side facing the release element with a guide region over which the spring arm is displaced during an axial adjustment of the release element guided against the spring force bias of the spring arm and thereby pivoted from its equivalent to the closed state of the locking device position in its the open state of the locking device equivalent position.

To further reduce the actuation force of the latching device and to improve the clamping protection of the device in the region between the spring arm and the piston unit, the release element is formed in a development of the subject invention on a spring arm facing end side with a guide surface over which the spring arm at an axial Adjustment of the release element against the spring force of the spring arm out and thereby pivoted from its the closed state of the locking device equivalent position in its the open state of the locking device equivalent position.

In a further advantageous embodiment of the locking device, the guide region of the spring arm and the guide surface of the release element cooperate with each other such that the spring arm guided against the spring force bias of the spring arm with an axial adjustment of the release arm with its guide area on the guide surface of the release element and thereby closed from his State of the locking device equivalent position in its the open state of the locking device equivalent position is pivoted.

Fig. 1

eine schematisierte Längsschnittansicht durch eine erfindungsgemäße Verriegelungsvorrichtung;

Fig. 2

eine stark schematisierte Einzelansicht der Kolbeneinheit und eines Federarms der Verriegelungsvorrichtung gemäß Fig. 1 in einer Längsschnittansicht;

Fig. 2a

eine Fig. 2 entsprechende Darstellung der Kolbeneinheit und des Federarms;

Fig. 2b

den in Fig. 2 dargestellten Federarm in einer Draufsicht in Alleinstellung;

Fig. 3a

eine Fig. 2 entsprechende Darstellung einer zweiten Ausführungsform der erfindungsgemäßen Vorrichtung gemäß Fig. 1;

Fig. 3b

die in Fig. 3a dargestellte Kolbeneinheit und den Federarm in einer Seitenansicht;

Fig. 4a

eine Fig. 3a entsprechende Darstellung einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung gemäß Fig. 1;

Fig. 4b

eine Fig. 3a entsprechende Darstellung der Kolbeneinheit und des Federarms gemäß Fig. 4a;

Fig. 5

zwei verschiedene Ausführungsformen der Kolbeneinheit und jeweils eines damit zusammenwirkenden Federarms, wobei der Rastbereich wenigstens bereichsweise konisch ausgeführt ist;

Fig. 6a

eine Draufsicht auf einen Federarm der in Fig. 1 dargestellten Verriegelungsvorrichtung;

Fig. 6b

eine Querschnittsansicht des Federarms gemäß Fig. 6a entlang einer Linie VIb-VIb;

Fig. 7a

eine zu der in Fig. 6a alternative Ausführungsform des Federarms der Verriegelungsvorrichtung gemäß Fig. 1;

Fig. 7b

eine Querschnittsansicht des Federarms gemäß Fig. 7a entlang der Linie VIIb-VIIb;

Fig. 8a

eine Draufsicht einer weiteren Ausführungsform eines Federarms der Verriegelungsvorrichtung gemäß Fig. 1;

Fig. 8b

den Federarm gemäß Fig. 8a in einer Querschnittsansicht gemäß der Linie VIIIb-VIIIb;

Fig. 9a

ein weiteres Ausführungsbeispiel des Federarms der Verriegelungsvorrichtung gemäß Fig. 1 in Alleindarstellung in einer Draufsicht;

Fig. 9b

eine Querschnittsansicht des Federarms gemäß Fig. 9a entlang der Linie IXb-IXb;

Fig. 10

eine Längsschnittansicht des in Fig. 7a dargestellten Federarms entlang der Linie X-X;

Fig. 11

eine mit dem in Fig. 10 dargestellten Federarm korrespondierende Biegelinie, welche die Funktionsweise der Verriegelungsvorrichtung gewährleistet;

Fig.12

eine nicht beanspruchte Ausführungsform eines mit im Wesentlichen über die gesamte Länge mit gleicher Biegesteifigkeit ausgeführten Federarm und

Fig. 13

eine mit dem in Fig. 12 dargestellten Federarm korrespondierende Biegelinie, welche die Funktionsweise der Vorrichtung in unerwünschtem Umfang beeinträchtigt.

Advantageous developments of the object according to the invention will become apparent from the embodiments described in principle with reference to the drawings, wherein in the description of the various embodiments for clarity, the same reference numerals are used for construction and functionally identical components.
It shows:

Fig. 1

a schematic longitudinal sectional view through a locking device according to the invention;

Fig. 2

a highly schematic single view of the piston unit and a spring arm of the locking device according to Fig. 1 in a longitudinal sectional view;

Fig. 2a

a Fig. 2 corresponding representation of the piston unit and the spring arm;

Fig. 2b

the in Fig. 2 illustrated spring arm in a plan view in isolation;

Fig. 3a

a Fig. 2 corresponding representation of a second embodiment of the device according to the invention Fig. 1 ;

Fig. 3b

in the Fig. 3a illustrated piston unit and the spring arm in a side view;

Fig. 4a

a Fig. 3a corresponding representation of a further embodiment of the device according to the invention Fig. 1 ;

Fig. 4b

a Fig. 3a corresponding representation of the piston unit and the spring arm according to Fig. 4a ;

Fig. 5

two different embodiments of the piston unit and each one cooperating spring arm, wherein the latching area is at least partially conical;

Fig. 6a

a plan view of a spring arm of in Fig. 1 illustrated locking device;

Fig. 6b

a cross-sectional view of the spring arm according to Fig. 6a along a line VIb-VIb;

Fig. 7a

one to the in Fig. 6a alternative embodiment of the spring arm of the locking device according to Fig. 1 ;

Fig. 7b

a cross-sectional view of the spring arm according to Fig. 7a along the line VIIb-VIIb;

Fig. 8a

a plan view of another embodiment of a spring arm of the locking device according to Fig. 1 ;

Fig. 8b

according to the spring arm Fig. 8a in a cross-sectional view according to the line VIIIb-VIIIb;

Fig. 9a

a further embodiment of the spring arm of the locking device according to Fig. 1 in solo view in a plan view;

Fig. 9b

a cross-sectional view of the spring arm according to Fig. 9a along the line IXb-IXb;

Fig. 10

a longitudinal sectional view of in Fig. 7a illustrated spring arm along the line XX;

Fig. 11

one with the in Fig. 10 illustrated spring arm corresponding bending line, which ensures the operation of the locking device;

Figure 12

an unclaimed embodiment of an executed over substantially the entire length with the same bending stiffness spring arm and

Fig. 13

one with the in Fig. 12 spring arm corresponding bending line, which affects the operation of the device to an undesirable extent.

A schematized longitudinal sectional view of a locking device 1 of a known parking brake device of a running with an automatic transmission drive train of a motor vehicle is in Fig. 1 shown. The locking device 1, in a manner known per se, has a piston unit 4 which can be acted upon by a fluid and actuated as a function of the fluid pressure against a spring device, which is not shown in the closing direction of the parking brake device, in the opening direction of the parking brake device. The piston unit 4 is displaceable in the axial direction in a housing 3 ,

The piston unit 4 is connected in the assembled state in a manner not shown with a parking rod of the parking brake device, wherein the parking rod is in turn operatively connected to a parking pawl that the parking pawl due to an axial movement of the piston unit and the associated parking rod with a with the Output of the drive train rotatably connected Parksperrenrad is engageable or out of engagement with the Parksperrenrad is feasible.

Furthermore, the locking device 1 is formed with a locking device 5, which automatically activates in a predefined position of the piston unit 4, for holding the piston unit 4 in the predefined position. In addition, the locking device 1 is designed with an electromagnetic actuator 6 for actuating a release element 7, which is provided for deactivating the latching device 5 and connected to a piston rod 8 and arranged longitudinally movable together with the piston rod 8 in the interior of the housing 3.

The piston rod 8 is connected at its piston unit 4 end facing the piston unit 4 via a spring ring 10, wherein the spring ring 10 is pressed in the axial direction via a spring element 11 against an inner stop 12 of the piston unit 4. This means that between the piston rod 8 and the piston unit 4, a relative movement within structurally predetermined limits against the spring force of the spring element 11 is possible, since the piston rod 8 with the piston unit 4 end facing into a bore 13 of the piston unit 4, in which also the Spring element 11 is arranged immersed.

Furthermore, the piston unit 4 is at its end facing away from the piston rod 8 with the parking lock device not shown in detail and with an emergency release device also not shown in operative connection that the piston unit 4 via the emergency unlocking device from the closed position of the parking brake device equivalent axial position in the open state of the parking brake device equivalent axial position is displaceable.

In addition, the piston rod 8 is at its end facing away from the piston unit 4 in a conventional manner with the emergency locking device in operative connection by means of the piston rod 8 and the associated release element 7 by an operator or a driver of the vehicle manually in the direction of Piston unit 4 is displaced to insert the parking brake device, if necessary, can.

In the Fig. 1 illustrated locking device 1, in the normal operating mode, during which the piston unit 4 is acted upon by a fluid pressure and the electromagnetic actuator is energized, the following operation on:

Starting from a in Fig. 1 shown operating state in which the release element 7 with its electromagnetic actuator 6 facing the end of this rests and an at least approximately conical portion 17 of the piston unit 4 is included by the latching device 5, the piston unit 4 is in an open state of the parking brake device equivalent axial position.

The latching device 5 is in the in Fig. 1 shown state of the locking device 1 is activated, so that the piston unit 4 by spring arms 5A, of which in Fig. 1 only one of preferably three evenly distributed over the circumference of the piston unit 4 arranged spring arms are shown, held such that an automatic insertion of the parking pawl is securely avoided even in non-applied fluid pressure in the annular space 18.

If the parking brake device is to be engaged on the basis of a desired driver input, which is preferably via a drive step selection device, the electromagnetic actuator 6 is energized such that the release element 7 together with the piston rod 8 in the direction of the piston unit 4 starting from the in Fig. 1 shown position between the spring arms 5A of the latching device 5 is pushed. In this case, the release element 7 comes with increasing displacement with its piston unit 4 facing the end, which is designed with a conical or conical guide surface 25, with a corresponding to the guide surface 25 of the release element 7 and at least approximately cylindrical guide portion 20 of the spring arms 5A so engaged in that the spring arms 5A are pressed by the release element 7 against a component and radially inwardly directed spring bias of the spring arms 5A ever further out until the frictional connection between the latching device 5 and the piston unit 4 between a contact surface 26 of the spring arms 5A and a Latching 27 of the piston unit 4, which adjoins a reduced diameter portion 19, is repealed.

Attacks on the piston unit 4 acting in the closing direction of the parking brake device resulting force component, which is composed in each case of the spring force acting on the piston unit 4 spring means and currently applied in the annular space 18 fluid pressure, the piston unit 4 is moved away from the electromagnetic actuator 6 until the parking lock device is engaged. When the parking brake device is engaged, the piston unit 4 is displaced from the engagement region of the spring arms 5A, so that the latching device 5 is deactivated. Subsequently, the energization of the electromagnetic actuator 6 is turned off, whereby the release element 7 due to the spring force of the spring element 11 again against the radial portion 16 of the latching device 5 in the in Fig. 1 shown manner is pressed. There the spring arms 5A are designed with a force acting in the direction of the central axis 14 of the device 1 spring bias, the spring arms 5A fold in the radial direction about a hinge portion 28 inwardly.

If the annular space 18 in the latter state of the device 1 in turn subjected to such a fluid pressure that acting on the piston unit 4 resulting force component acts in the direction of the release element 7, the piston unit 4 from its the closed state of the parking brake device equivalent axial position in the direction the electromagnetic actuator 6 is displaced until the latch 5 is activated in the manner described above.

The piston unit 4 is due to the prevailing in the limited by the housing 3 and the piston unit 4 annular space 18 fluid pressure, which may be hydraulically or pneumatically generated, adjusted from its closed state of the parking brake device equivalent axial position in the direction of the electromagnetic actuator 6 in the axial direction , During the axial adjustment of the piston unit 4, the spring arms 5A of the latching device 5 folded in the direction of the center axis 14 of the device 1 are each starting from their ends facing the piston unit 4 with increasing displacement of the piston unit 4 via the end of the piston unit 4 facing the actuating device 6 conically or conically executed area 17 of the piston unit 4 out.

Due to the force acting in the direction of the piston unit 4 spring bias of the spring arms 5A, the spring arms 5A come after passing over the conical portion 17 on the piston unit 4 in a reduced diameter portion 19 of the piston unit 4 with its piston unit 4 facing contact surface 26 behind the conical portion 17 on the locking portion 27th to the concern. Since both the spring arms 5A with their contact surfaces 26 and the piston unit 4 with their latching region 27 each facing each other Paragraphs are executed and are provided with activated locking device 5 as abutment areas between the spring arms 5A and the piston unit 4, the piston unit 4, despite acting on her resulting force component, which acts in the closing direction of the locking mechanism of the latching device 5 in the in Fig. 1 shown position due to the present in the paragraphs non-positive connection between the spring arms 5A and the piston unit 4 is held.

The resulting force component acting in the closing direction of the parking brake device then acts on the piston unit 4 when the spring force of the spring device is greater than the hydraulic or pneumatic pressure force of the annular space 18 acting on the piston unit 4.

Furthermore, the in Fig. 1 illustrated locking device 1 carried out such that the locking device in a system failure of the above-described operation required control system, in which neither a fluid pressure in the annular space 18 is ready to actuate the piston unit 4 still energizing the electromagnetic actuator 6 is possible in its last assumed state, ie opened or closed, remains. So that the parking brake device can still be controlled, the emergency unlocking device and the emergency locking device are provided, which offer a driver the opportunity to manually unlock the currently engaged parking brake device or manually insert the currently designed parking brake device can.

In Fig. 2 to Fig. 5 are five different embodiments of the locking device according to the invention according to Fig. 1 shown, wherein both the piston unit 4 and the spring arm 5A are partially carried out differently in the manner described below, in order to the above-described Functioning of the locking device 1 to ensure safe.

In the Fig. 2 to Fig. 5 shown different embodiments of the spring arm 5A and the piston unit 4 differ substantially in the area of the contact surface 26 and the latching portion 27 of the piston unit 4, so that in the description of the second, third, fourth and fifth embodiment of the locking device 1 according to the invention only to the differences the in Fig. 2 to Fig. 2b illustrated first embodiment of the spring arm 5A and the piston unit 4 is discussed in more detail.

Further referring to Fig. 2 , in which the spring arm 5A and the piston unit 4 are shown alone in a longitudinal sectional view, the inventive design of the spring arm 5A in conjunction with the illustration of Fig. 2a showing a side view of the piston unit 4 and three spring arms 5A to 5C operatively connected thereto, as well as in connection with the illustration of FIG Fig. 2b , which is a plan view of the spring arm 5A according to Fig. 2a and Fig. 2b shows, explained in more detail.

The in Fig. 2 shown spring arm 5A has a side rail portion 33 which forms a longitudinal plane of the spring arm 5A substantially. A recess 41 is punched out of the longitudinal carrier region 33, wherein at least a part of the punched-out region is bent in the direction of the piston unit 4 in the form of a tab 42 by at least 90 ° relative to the longitudinal carrier region 33 or the longitudinal plane of the spring arm 5. The piston unit 4 rests with its latching region 27 on the contact surface 26 formed by the tab 42 flush with the spring arm 5A and is counter to a holding force indicated by the arrow F in the in Fig. 2 held position held.

The conical region 17 of the piston unit 4 is presently designed in its largest diameter range with such a diameter that the piston unit 4 with its conical region 17 at least approximately reaches through the recess 41 of the spring arm 5A in the radial direction. This ensures that the latching portion 27 of the piston unit 4 is arranged in the locked state of the piston unit 4 at least in one of the longitudinal plane of the spring arm 5A near range and the holding force with a lever arm x, which represents only a small distance from the longitudinal plane of the spring arm 5A, is introduced into the spring arm 5A. As a result, the spring arm 5A is impressed by the applied holding force only a small bending moment.

At the same time, the spring arm 5A in the region of the tab 42, d. H. also in its a predetermined breaking point performing curved area, claimed in the provided during the preparation of the spring arm 5A bending direction by the holding force F. The spring arm 5A has in the bending region of the tab 42 thus in a simple manner a longer life, since the tab 42 is not acted upon against the bending device during bending forming and present in the bending area production inherent stresses with the holding force.

The lever arm x results in the in Fig. 1 and Fig. 2 illustrated embodiment of the spring arm 5A from the conical region of the piston unit 4 facing bending radius R5A of the bending region of the tab 42, since a line contact or a flat contact between the spring arm 5A and the latching portion 27 of the piston unit 4 only after the transition from the bending radius R5A in the level bearing surface 26 is present.

In order to lay the surface contact or the line contact between the spring arm 5A and the piston unit 4 directly in the longitudinal plane of the spring arm 5A, a post-processing of the spring arm 5A is required, the Bending radius in the area of the longitudinal plane eliminated. This can be achieved, for example, by milling, grinding or similar manufacturing methods, but this increases the manufacturing costs of the spring arm 5A.

From the illustration according to Fig. 2a shows that the piston unit 4 next to the in Fig. 2 illustrated spring arm 5 A of two further identically designed spring arms 5 B and 5 C, which are arranged distributed uniformly over the circumference of the piston unit 4 is held. Additionally goes from the presentation according to Fig. 2a show that the tabs 42 of the spring arms 5A to 5C in the region of the piston unit 4 facing free ends are designed with circular segment-like recesses, so that the spring arms 5A, 5B and 5C in the manner required for the locking of the piston unit 4 way in the direction of reduced diameter range 19 of the piston unit 4 can spring, without coming to rest on this, before the locking portion 27 is disposed substantially in the longitudinal plane of the spring arms 5A to 5C and the lever arm x assumes an undesirably large value.

Fig. 2b shows the spring arm 5A according to Fig. 2 and Fig. 2a in a plan view, in which the advantageous for a notch effect embodiment of the recess 41 in the region of the tab 42 is shown in more detail. The punching contour of the recess 41 in the region of the tab 42 is in each case designed with punching radii R41A, R41B required for a low notch effect.

In Fig. 3 is a second embodiment of the locking device 1 according to the invention Fig. 1 shown.

In addition to the recess 41, the spring arms 5A and 5B and 5C in the longitudinal beam region with bends 32 are designed to increase a flexural rigidity of the spring arm 5A and the spring arms 5B and 5C in the longitudinal direction, wherein the bends 32 optionally executed at right angles or rounded may be to provide the smoothest possible transition to the side rail portion 33.

In addition, it is provided in the present case, the contact surface 26 with respect to the latching portion 27, which is arranged substantially perpendicular to the longitudinal axis of the piston unit 4, with a so-called self-locking angle α, which may be provided in the range of 0 ° to 5 °. By means of the self-locking angle α, a detent force opposing the release of the locking device can be varied in a simple manner as a function of the particular application in question. In this case, between the contact surface 26 of the spring arm 5A and the latching portion 27 of the piston unit 4 at a self-locking angle of 0 ° substantially a locking force increasing surface contact before, while self-locking angles greater than 0 ° between the piston unit 4 and the spring arm 5A, the surface pressure further increasing and the locking force simultaneously reducing line contact is given.

Fig. 4a and Fig. 4b show a third embodiment of the locking device 1 according to Fig. 1 which essentially corresponds to the second exemplary embodiment Fig. 2 to Fig. 2b corresponds, wherein the self-locking angle α is provided to reduce the release force of the locking device 1 opposite locking force in the region of the tab 42. This means that the tab 42 on the side facing away from the latching portion 27 of the piston unit 4 includes an angle between 90 ° and 95 ° to reduce the locking force, with increasing self-locking angle α, the value of the lever arm x increases. Furthermore, the spring arm 5 has no bends 32 in the longitudinal member region 33. This saves costs and on the other hand can be specifically taken to influence the bending line de spring arm 5.

In addition, however, it is also possible to vary the self-locking angle α to reduce the locking force both by appropriate design measures in the area of the contact surface 26 and in the latching portion 27 of the piston unit 4. In such cases, the latching portion 27 in the in Fig. 5 illustrated manner cone-shaped and includes with a plane perpendicular to the longitudinal axis of the piston unit 4 level an acute angle between 0 ° and 5 °. At the same time, the lug 42 is bent relative to the longitudinal carrier region 33 such that the lug 42 encloses an angle of less than 90 ° with the longitudinal carrier region 33 on the side facing away from the latching region 27. In this case, it is provided that the self-locking angle α resulting from the bending angle of the flap 42 with respect to the longitudinal carrier region 33 and the conical design of the latching region 27 preferably does not exceed a total of 5 °.

Fig. 6a to Fig. 9b show various embodiments according to the invention of a spring arm 5A, which is in each case partially formed with different bending stiffnesses to ensure the above-described operation of the locking device 1 can safely.

In the Fig. 6a to Fig. 9b shown various other embodiments of the spring arm 5A differ essentially in the measures selected in each case to increase the flexural rigidity, so that in the description of the embodiment of the spring arm 5A according to Fig. 7a to 9b only to the differences to the in Fig. 6a and 6b illustrated embodiment of the spring arm 5A closer reference.

Further referring to Fig. 6a , in which a spring arm 5A is shown alone in a plan view, the inventive design of the spring arm 5A in conjunction with the illustration of Fig. 6b which is a cross-sectional view of the spring arm 5A according to Fig. 6a along the line Vlb-Vlb shows, explained in more detail.

The spring arm 5A is designed substantially T-shaped, wherein a transverse support portion 30 of the spring arm 5A inserted in the assembled state in a groove 31 of the fixedly connected to the housing 3 of the device 1 actuator 6 and connected during normal operation of the device 1 is not detachably connected thereto is. The cross member area 30 is provided with a in Fig. 1 shown and executed with a substantially 90 ° bent support portion 29 whose free end is at least partially disposed in the groove 31 of the actuator 6 and connected via a press fit firmly with this.

The joint region 28 adjoins the transverse support region 30 and is arranged between the transverse support region 30 and the longitudinal support region 33 of the spring arm 5A. The hinge portion 28 is designed due to the above-described functionality of the spring arm 5A with a lower bending stiffness than the side rail portion 33, so that the spring arm 5A to the hinge portion 28 in the zu Fig. 1 described in more detail from the release element 7 is radially pivotable. The longitudinal beam region 33 is designed starting from the joint region 28 to its end with a continuously increasing width and formed in the region of its longitudinal sides with bends 32, so that the side rail portion 33 is formed in cross-section at least approximately U-shaped.

The joint region 28 of the spring arm 5A is presently formed with substantially the same width and without bending and thus has in comparison to the side rail portion 33, a lower flexural rigidity, whereby the spring arm 5A in the hinge region 28 with the desired or required for the pivoting of the tab 42 component elasticity is executed.

Due to the increasing width with increasing distance and the U-shaped configuration of the side rail portion 33 of the spring arm 5A in the side rail portion 33 is designed with such a flexural rigidity that a degree of deformation of the spring arm 5A during deactivation of the latching device 5 is smaller than a release of the operative connection between the spring arm 5A and the piston device 4 preventing deformation, which in this context to the following and this fact further explanatory description 10 to FIG. 13 is pointed out.

In addition, the tab 42 of the spring arm 5A in the region of the piston unit 4 facing the free end 21 is designed with a circular segment shape, which is adapted to the cylindrical contour of the piston unit 4 in the reduced diameter portion 19 such that the spring arm 5A in the region of the free end 21 of Tab 42 substantially over the entire circular arc on the lateral surface of the reduced diameter portion 19 of the piston unit 4 comes to rest. Thus, a surface of the overlap region between the latching region 27 of the piston unit 4 and the abutment surface 26 of the spring arm 5A compared to a straight embodiment of the free end 21 of the tab 42 is optimized such that a surface pressure in the overlap region is low and the piston unit 4 in the latching region 27th with a lower component strength with respect to such a load is executable.

In the present case, the latching region 27 of the piston unit 4 encloses an angle of 90 ° with the lateral surface of the reduced diameter region of the piston unit 4. Furthermore, it is provided that the tab 42 is designed with such an elasticity that the contact area between the tab 42 and the latching portion 27 in the activated state of the latching device 5 assumes the largest possible value. This means that the tab 42 is deformed with activated latching device 5 to such an extent is that in the overlapping region of the spring arm 5A and the piston unit 4 at least one line-shaped, but preferably sets a flat, support and the surface pressure is low.

This also means that the tab 42 and the latching area 27 cooperate in the overlapping area in each case such that a perpendicular to the direction of movement of the piston unit 4 standing plane 15, which in this case also with the lateral surface of the reduced diameter portion 19 forms an angle of 90 °, and a Touch plane 16 of the overlap region between the latching portion 27 and the tab 42 under a required in each case for the proper functioning of the device 1 self-locking angle a intersect. The in Fig. 1 illustrated self-locking angle α varies depending on a coefficient of friction between the abutment surface 26 of the spring arm 5A and the latching portion 27, each depending on the particular application, between 0 ° and 5 ° C. Thus, a self-locking angle of about 5 ° for the operation of the device 1 is advantageous if both the spring arm 5A and the piston unit 4 are made in the overlap region of the two components made of steel.

At the in Fig. 7a illustrated embodiment of the spring arm 5A is the side rail portion 33 in contrast to the in Fig. 6a shown spring arm 5A running with the same width. Otherwise, the spring arms according to Fig. 6a or according to Fig. 7a the same design. Fig. 7b shows the spring arm 5A according to Fig. 7a in a cross-sectional view along the line VIIb-VIIb with bends 32 and bends, which are directed in the mounted state of the spring arm 5A radially in the direction of the release element 7. Of course, it is within the skill of the art to bend the bends 32 in the opposite direction to increase the flexural stiffness of the side rail portion 33 in the desired manner.

Fig. 8a shows a further embodiment of a spring arm 5A in a representation according to Fig. 7a and 7b , The spring arm 5A according to Fig. 8a is embodied in the longitudinal beam region 33 with two reinforcing beads 34 extending in the longitudinal direction of the spring arm 5A, which are each positioned next to the guide region 20 machined out of the longitudinal beam region 33 during a punching and bending process and extend essentially over the entire length of the longitudinal beam region 33. The configuration of the stiffening beads 34 is in the cross-sectional view according to Fig. 8b along the line VIIIb-VIIIb shown closer and inexpensive manner in the longitudinal beam portion 33 produced.

In Fig. 9a a further embodiment of the spring arm 5A of the device 1 is shown, which is substantially of the in Fig. 6a to Fig. 8b illustrated embodiments essentially only in the side rail portion 33 differs. The longitudinal beam portion 33 of the spring arm 5A according to Fig. 9a is substantially made in two parts, wherein a first portion 33 A, which is between the hinge portion 28 and the second portion 33 B is designed with the guide portion 20 and the recess 41, is arranged. The first portion 33A is formed starting from the hinge portion 28 to the second portion 33B with a continuously increasing width and with two parallel to the outer sides extending from the surface of the side rail portion 33 unilaterally punched out and bent down stiffening regions 35A and 35B, wherein the Stiffening portions 35A and 35B extend into the second portion 33B of the side rail portion 33. The second portion 33B of the side rail portion 33 is made longitudinally of constant width and on its outside in the same manner as the spring arms 5A in FIG Fig. 6a respectively. Fig. 7a formed with bends 32, so that the second portion 338 of the side rail portion 33 in the in Fig. 9b in which the spring arm 5A according to Fig. 9a in a cross-sectional view along the line IXb-IXb is shown, the manner shown at least approximately U-shaped executed.

Fig. 10 shows the in Fig. 7a illustrated spring arm 5A in a longitudinal sectional view along the line XX in a no-load condition. The tab 42 and the Längsträgerbreich 33 of the spring arm 5A close in no-load condition at least approximately an angle of 90 °.

Additionally is in Fig. 11 a under load, ie during actuation of the spring arm 5A according to Fig. 10 through the release element 7, which leads the spring arm 5A out of engagement with the piston unit, adjusting bending line 22 is shown. From the illustration according to Fig. 11 It can be seen that the spring arm 5A according to Fig. 10 deformed under load substantially over its entire length at least approximately parabolic. Both the cross member area 30, and the side rail portion 33 and the tab 42 are deformed such that the tab 42 under load occupies the required for compliance with the self-locking angle α arrangement with respect to the latching portion 27 of the piston unit 4. In this case, it is possible to design the spring arm 5A such that the angle between the tab 42 and the side rail region 33 changes under load such that the self-locking angle α required for a trouble-free release of the operative connection between the spring arm 5A and the piston unit 4 is established ,

Deviating from this, however, the spring arm 5 A can also be embodied in the transition region between the tab 42 and the longitudinal carrier region 33 with such rigidity that the angle between the tab 42 and the longitudinal carrier region 33 does not change under load and the self-locking angle α in the overlapping region due to a corresponding deformation of the remaining portions of the spring arm 5A sets.

In the unclaimed embodiment according to Fig. 12 is one too Fig. 10 corresponding representation of a spring arm 40 shown in contrast to the in Fig. 10 shown spring arm in the longitudinal beam portion 33 without the above-described stiffening measures and without recess 41 and without tab 42 is executed, so that the spring arm 40 is formed over its entire length with a substantially constant bending stiffness and the holding force with a large lever arm x in the spring arm 40 is initiated.

Fig. 13 represents a bending line 23 of the spring arm 40, which adjusts during actuation of the spring arm 40 by the release element 7, ie under load, during deactivation of the latching device 5.

Upon closer inspection of the bending line 23 of the spring arm 40 it can be seen that the spring arm 40 in the attack region of the release element 7, ie in the guide portion 20 of the spring arm 40 has a strong bulge, so that a claw region 50, which is as large as possible at activated latching device 5 at the latching area 27 of the piston unit 4 is applied, in the in Fig. 13 shown manner is pivoted away about the free end 21 to a considerable extent from the latching region 27 and the required for proper functionality of the device 1 self-locking angle α between the claw region 50 and the latching region 27 is no longer present.

The in Fig. 13 shown degree of deformation of the spring arm 40 is disadvantageously such that the self-locking angle α in the coverage area between the claw region 50 of the spring arm 40 and the piston unit 4 is changed so much that the spring arm 40 due to high friction forces in the overlap region between the claw region 50 of the spring arm 40 and the Latching 33 of the piston unit 4 can no longer be out of engagement with the piston unit 4 and thus a functional blockage of the locking device 1 is hardly avoidable. In this case, the cross member portion 30 and the claw portion 50 of the spring arm 40 disadvantageously so-called clamping points of the spring arm 40, between which the spring arm 40 by acting on the guide portion 20 release member 7 in the in Fig. 13 is deformed manner without disabling the latching device 5.

In addition, the claw region 50 of the spring arm 40 is loaded against its bending direction provided during production. This load is disadvantageous and leads to an undesirable reduction in the life of a spring arm, since the bent portion between the side rail portion 33 and the claw region 50 is a predetermined breaking point, the strength at a load against the Herstellbiegerichtung is substantially lower than a load in Herstellbiegerichtung how it is provided in the locking device 1 according to the invention.

reference numeral

1

contraption

3

casing

4

piston unit

5

locking device

5A

spring arm

6

actuator

7

release element

8th

piston rod

10

spring washer

11

spring element

12

inner stop

13

drilling

14

central axis

15

vertical plane

16

contact plane

17

conical region of the piston unit

18

annulus

19

reduced diameter range of the piston unit

20

Guide area of the spring arms

21

free end of the tab

22

elastic line

23

elastic line

25

Guide surface of the release element

26

contact surface

27

Rest area

28

joint area

29

holding section

30

Cross member area of the spring arm

31

groove

32

bends

33

Longitudinal support area

33A

first section of the side rail area

33B

second section of the side rail area

34

reinforcing beads

35A, 35B

stiffening areas

40

spring arm

41

recess

42

flap

50

claws area

R5A

bending radius

R41A

punching radius

R41 B

punching radius

α

Self-locking angle

Claims (12)

1. Locking apparatus (1), in particular a parking immobilizer of a drive train, embodied with an automatic transmission, of a vehicle, which has a piston unit (4) which is arranged so as to be displaceable in the axial direction in a housing (3) and can be locked in a predefined axial position, and a latching device (5), which can be automatically activated in the locked position of the piston unit, in order to secure the piston unit (4), wherein the latching device (5) is embodied with at least one spring arm (5A, 5B) which is operatively connected to the piston unit (4) in the locked position of the piston unit (4), against which arm (5A, 5B) the piston unit (4) bears with a latching region (27) in the locked position, characterized in that the spring arm (5A) is embodied with a recess (41), and the piston unit (4) at least approximately engages through the recess (41) in the spring arm (5A) in the radial direction with a section which forms the latching region (27), with the result that in the locked state of the piston unit (4) the latching region (27) of the piston unit (4) is arranged at least in a region which is close to the longitudinal plane of the spring arm (5A), preferably in the longitudinal plane of the spring arm (5A).
2. Locking apparatus according to Claim 1, characterized in that a bearing face (26) of the spring arm (5A) for the latching region (27) of the piston unit (4) is embodied as a side face which bounds the recess (41) in the longitudinal plane of the spring arm (5A).
3. Locking apparatus according to Claim 1 or 2, characterized in that the recess (41) is manufactured by punching.
4. Locking apparatus according to Claim 3, characterized in that the recess (41) is manufactured by punching in a certain region and by bending over the punched-out region (42) with respect to the longitudinal plane of the spring arm (5A), wherein, in the locked state, the piston unit (4) bears against the region (42) which is bent out of the longitudinal plane of the spring arm (5A) and loads the bent region (42) in the bending direction.
5. Locking apparatus according to Claim 3 or 4, characterized in that a punching radius (R41A, R41B) has, in the region of the bearing face, a value which minimizes a notch effect.
6. Locking apparatus according to one of Claims 1 to 5, characterized in that the spring arm (5A) is embodied with an essentially U-shaped cross section at least in certain sections, wherein the spring arm (5A) preferably has bent-over portions (32) which are directed radially and tangentially in a longitudinal carrier region (33) and which give rise to the essentially U-shaped cross section of the spring arm (5A).
7. Locking apparatus according to one of Claims 1 to 6, characterized in that the spring arm (5A) is embodied, at least in a certain region, with at least one reinforcing bead (34) which runs essentially in the longitudinal direction of the spring arm (5A).
8. Locking apparatus according to one of Claims 1 to 7, characterized in that the spring arm (5A) is embodied, at least in a certain region, with at least one reinforcing region (35A, 35B) which runs essentially in the longitudinal direction of the spring arm (5A).
9. Locking apparatus according to one of Claims 1 to 8, characterized in that at least line contact, preferably support over a surface, occurs between the bearing face (26) which can be placed in congruence with the latching region (27) of the piston unit (4) in the mounted state of the spring arm (5A) and the latching region (27) of the piston unit (4) in the activated state of the latching device (5).
10. Locking apparatus according to Claim 9, characterized in that the spring arm (5A) is embodied in the region of the bearing face (26) with a contour which is adapted to the external shape of the piston unit (4) in such a way that a face of the congruent region between the latching region (27) of the piston unit (4) and the bearing face (26) of the spring arm (5A) is at a maximum.
11. Locking apparatus according to Claim 9 or 10, characterized in that the bearing face (26) and the latching region (27) are respectively embodied in the congruent region in such a way that a plane (15) which is perpendicular to the direction of movement of the piston unit (4) and a contact plane (16) of the congruent region between the latching region (27) and the bearing face (26) intersect at an angle (α) of 0° to 5° during operational loading.
12. Locking apparatus according to one of Claims 1 to 11, characterized in that the spring arm (5A) is manufactured from a spring steel material.

Images